The present invention relates to vehicle power management systems and, more particularly, to vehicle power management systems for vehicles having at least one engine driven component.
In most motor vehicles driven by internal combustion engines, only a fraction of the potential energy available from the fuel is actually used to drive the vehicle's drive wheels. Various other components are driven by the engine and use up some of the energy that would otherwise be available for driving the drive wheels. In addition, there are losses due to incomplete combustion, heat losses, the exhaust system, and friction. Also, when vehicles travel downhill, a substantial amount of kinetic energy is wasted because vehicle or engine brakes must be used to slow the vehicle down.
To illustrate, when a truck with a 350 HP engine is driven with an engine speed of about 1800 RPM is driven uphill and the engine is operated at its maximum load, typically approximately 50 HP is used to operate the engine fan, approximately 9 HP is used to operate the alternator, approximately 7 HP is used to operate the air conditioner compressor, and between 7-12 HP is used to operate the brake air compressor. This means that only about 270 HP of the total 350 HP available can be used to drive the vehicle's drive wheels. Often, a substantially greater fraction of the total available horsepower is not used to drive the vehicle's drive wheels.
When it is desired to slow the vehicle down, or to keep the vehicle within a desired speed range when the vehicle is driven downhill, the engine typically operates at substantially less than maximum load. At the same time, energy is often wasted to brake the vehicle.
It is desirable to provide a vehicle with a means of using more of its available engine power to drive the drive wheels of the vehicle when the engine is under high load. It is also desirable to provide a vehicle with a means of using braking energy to power vehicle components that would otherwise be powered by the vehicle's internal combustion engine.
In accordance with an aspect of the present invention, a vehicle with a power management system comprises a battery, an internal combustion engine adapted to deliver power to a vehicle load, a battery powered component powered by the battery, an engine powered component powered by the engine, the battery powered component and the engine powered component being adapted to perform substantially the same functions, and a controller arranged to stop operation of the engine powered component so that additional engine power is available to the vehicle load, and to initiate operation of the battery powered component, when power sought to be delivered to the vehicle load from the engine reaches a predetermined percentage of maximum engine load.
In accordance with another aspect of the present invention, a method for managing power in a vehicle comprises monitoring an amount of power sought to be delivered from the vehicle's engine to a vehicle load, operating an engine powered component powered by the engine when the amount of power sought to be delivered from the vehicle's engine to the vehicle load is no greater than a predetermined percentage of maximum engine load, and stopping operation of the engine powered component so that additional engine power is available to the vehicle load and operating a battery powered component powered by a battery and adapted to perform substantially the same function as the engine powered component when the amount of power sought to be delivered from the vehicle's engine to the vehicle load exceeds the predetermined percentage of maximum engine load.
In accordance with yet another aspect of the present invention, a method for making a vehicle with a power management system comprises installing in a vehicle a battery, an internal combustion engine adapted to deliver power to a vehicle load, a battery powered component powered by the battery, and an engine powered component powered by the engine, the battery powered component and the engine powered component being adapted to perform substantially the same functions. The method also comprises programming a controller to stop operation of the engine powered component so that additional engine power is available to the vehicle load, and to initiate operation of the battery powered component, when power sought to be delivered to the vehicle load from the engine reaches a predetermined percentage of maximum engine load.
In accordance with yet another aspect of the present invention, a power management system is provided for a vehicle having an internal combustion engine adapted to deliver power to a vehicle load for propelling the vehicle and an engine powered component powered by the engine. The system comprises a battery, a battery powered component powered by the battery, the battery powered component and the engine powered component being adapted to perform substantially the same functions, and a controller arranged to stop operation of the engine powered component so that additional engine power is available to the vehicle load, and to initiate operation of the battery powered component, when power sought to be delivered to the vehicle load from the engine reaches a predetermined percentage of maximum engine load.